253 high idle

[kingswood country]

Would one be able to tell me why the old girl, Holley 253 red, idles so high in park and neutral, but so low in gear?
I've never been able to work that one out.

 

[Kiddo]

I know nothing about these engine, but maybe a vaccum leak?

 

[fatboyvk]

how high are we talking

 

[kingswood country]

I can't be exact, I've got it set a little higher than factory, so about 900rpm, I can't go lower as it's too low in gear now. There's no vac leaks, it's got bugger all to leak

 

[ari666]

tuning is always done in gear (D,1,2,R) idle is set to 850RPM, timing set to around 10 deg BTDC, mixtures then set, then idle lowered back to 850RPM.

you will find thatgetting the tune right will mean the difference between the engine "freewhelling" in P and N and being in gear is a lot less. too much timing, too high idle or too rich mixtures seem to fk with D (i have noticed) but when you get them all set right, you should be able to take your foot off the brake up a very slight hill and not roll forward, and the difference in revs between D and P isnt that much. (maybe 850 in D and 1000 in P)

 

[kingswood country]

Thanks again ari, I didn't put it in d when I tuned it last, I left it in p, it's never REALLY bothered me, just always wondered why.
Think I may retune on the weekend

 

[jpetrou]

Can you identify the type of engine in your Kingwood ? If your engine is a pre-emission (July 1976), your idle speed should be set at 500 to 600 rpm in drive for auto. If your engine was changed to a later emission control version (after June 1976), the idle speed is set at 625 -650 rpm in drive for auto. My HZ 253 (emission model) Isles at 650 rpm in drive and when you slot the Trans in park/neutral the rpm rises to 900rpm. You might also check your distributor timing as it varies with emission and pre-emission engines.

 

[kingswood country]

Pre pollution. She hasn't got a tach, so it's all by ear nor do I have a timing light, she runs well, so it's not much of a concern to be honest. I'll just give it a tune on Sunday and see how we go, I Spose the Holley wouldn't be helping either

 

[kingswood country]

Funnily enough, now it won't idle!

Runs great under load, but as soon as you back off, it doesn't like it,
at a constant slow pace it kind of feels like I'm pulling a trailer over bumps, or like ive just started it and driving it cold without a choke but it's certainly not cold!, it's the best way I can describe it.
Every now and then it idles fine,
Hasnt lost any power.
But on the occasion, if I hold the foot flat like it's flooded and start it, it'll be fine...... For a while.

When I stop and pull the choke out, she idles fine,

I've retuned the carby starting from scratch because I thought it may have been that,
Idle mixture, idle reset, float level and re adjust accelerator pump.

There are no vacuum leaks.

It's not the dizzy, just fitted a new hei, had the problem to start with.

Leads are new too.

I feel like it's something to do with the carby.
The next step is changing fuel filter, but it's relatively new.

It started around the same time as it nearly ran dry, and topped it up with fuel siphoned from the commodore.

Bit I can't be sure wether before or after, I don't remember.
But in saying that, the commodore ran like **** too and I haven't sourced that problem either.

I'll ask here first before I start a new thread.

And for memory sake, pre emissions red 253 with 350 Holley.

I'm yet to put the quady on.
One day on the near future.

 

[drewVHSS]

really sound's like carby or split diaphram in the fuel pump issue

I'm not too up with holley's but I'll support your move to a quaddy any day of the week!